Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA.
Department of Applied Physics, Stanford University, Stanford, California 94305, USA.
Nat Commun. 2014 Sep 25;5:5017. doi: 10.1038/ncomms6017.
Fully lithiated lithium sulphide (Li2S) is currently being explored as a promising cathode material for emerging energy storage applications. Like their sulphur counterparts, Li2S cathodes require effective encapsulation to reduce the dissolution of intermediate lithium polysulphide (Li2Sn, n=4-8) species into the electrolyte. Here we report, the encapsulation of Li2S cathodes using two-dimensional layered transition metal disulphides that possess a combination of high conductivity and strong binding with Li2S/Li2Sn species. In particular, using titanium disulphide as an encapsulation material, we demonstrate a high specific capacity of 503 mAh g(-1)(Li2S) under high C-rate conditions (4C) as well as high areal capacity of 3.0 mAh cm(-2) under high mass-loading conditions (5.3 mg(Li2S) cm(-2)). This work opens up the new prospect of using transition metal disulphides instead of conventional carbon-based materials for effective encapsulation of high-capacity electrode materials.
完全锂化的硫化锂（Li2S）目前正被探索作为新兴储能应用的一种有前途的阴极材料。与它们的硫对应物一样，Li2S 阴极需要有效的封装，以减少中间锂多硫化物（Li2Sn，n=4-8）物种溶解到电解质中。在这里，我们报告了使用二维层状过渡金属二硫化物来封装 Li2S 阴极，这些二硫化物具有高导电性和与 Li2S/Li2Sn 物种强结合的组合。特别是，使用二硫化钛作为封装材料，我们在高 C 率条件（4C）下展示了 503 mAh g(-1)(Li2S)的高比容量，以及在高质量负载条件（5.3 mg(Li2S)cm(-2)）下 3.0 mAh cm(-2)的高面积容量。这项工作为使用过渡金属二硫化物代替传统的基于碳的材料来有效封装高容量电极材料开辟了新的前景。
